부산대학교 도서관

This study carried out zeta potential measurements of Chlorella sp. under various solution conditions and investigated its characteristics through implementation of size control of the microbubbles in order to eliminate algae whichis problematic for both aquatic ecosystems and human activities. The DAF process was adopted and several coagulants were used to remove the Chlorella sp. A CCD Camera was used to measure and analyze the sizes of the microbubbles, and a fluorescent microscope was used to observe particles, algae species, and the community as a whole. Zeta potential behavior of the algae was analyzed using ELS-Z. Both lab-scale and pilot-scale experiments were conducted to test the flotation process. Polyaluminium chloride(PAC) coagulant was used, and the removal efficiency of the algae was assessed through chlorophyll-a analysis. In the lab-scale experiment, 2.2 mg/L, 11 mg/L, 22 mg/L, and 44 mg/L of polyaluminium chloride were injected to coagulate the algae. The microbubbles, whichwere generated at an air pressure of 450-550 kPa, caused the coagulated algae to float. The microbubble size was controlled at 36 ㎛, 100 ㎛, and 200 ㎛ by using different diffusers. The results of the lab-scale experiments on the flotation plant indicated that the average removal rate was about 90% or above for 11 mg/L, 22 mg/L, and 44 mg/L of polyaluminium chloride. On the other hand, in the pilot-scale experiment, the removal efficiency was 85%-95% in all dose ranges of polyalumium chloride and aluminium sulfate coagulants.